I bought the following Bible Dictionary: Longman, T., III, Enns, P., & Strauss, M., (2013). The Baker Illustrated Bible Dictionary.
I prioritized this resource above my other Bible Dictionaries. Anybody an idea why it does not show up in the following list when I search on a headword like 'Sanhedrin'?

The dictionary does have an entry for 'Sanhedrin'.
